The Lot Sizing Problem with Return and Profit Maximisation

We address the lot sizing problem without capacity with return and price. The goal is to maximize profit and minimize total costs while meeting customer demands that include new product demands and used product demands The problem addressed in this work is one of the lot sizing problems with remanufacturing found in the literature and our addition is to introduce the purchase price of returns as a decision variable. The problem of lot sizing with return has received a lot of attention from many scientists due to the importance of the subject in manufacturing systems In particular, studies on remanufacturing, refurbishment and prices Simultaneous, which is very rare in literature. In this study, we include three processes: refurbishment, disassembly and remanufacturing of parts, and assembly of new products. The process feeds on the requirements of second-hand (refurbished) and New products. we propose a mathematical model for this problem, and We conducted numerical tests to examine the impact of corresponding decisions on the overall profit in various scenarios. the results show that the integration of the purchase price of returns as a decision variable, refurbishing process can lead to a significant profit gain.